1. Field of the Invention
The present invention relates to an electrode for a power storage device and a power storage device including the electrode.
Note that the power storage device indicates all elements and devices which have a function of storing power.
2. Description of the Related Art
In recent years, power storage devices such as lithium-ion secondary batteries, lithium-ion capacitors, and air cells have been developed.
An electrode for a power storage device is manufactured by forming an active material layer over one surface of a current collector. As the active material, a material which can occlude and release ions, such as carbon or silicon, is used. In addition, phosphorus-doped silicon has larger theoretical capacity than carbon and thus is advantageous in terms of increasing capacity of a power storage device (see Patent Document 1).
Owing to excellent electric characteristics such as high conductivity (high electron mobility) and physical characteristics such as flexibility and mechanical strength, application of graphene to a variety of products has been attempted (see Patent Documents 2 and 3). In addition, a technique for applying graphene to a lithium-ion secondary battery has been proposed (see Patent Document 4).